CVE-2018-25115
📋 TL;DR
This CVE describes an unauthenticated remote command execution vulnerability in multiple D-Link DIR-series routers. Attackers can send specially crafted HTTP POST requests to the service.cgi endpoint to execute arbitrary system commands with root privileges. Affected users are those running vulnerable firmware on listed D-Link DIR router models.
💻 Affected Systems
- D-Link DIR-110
- D-Link DIR-412
- D-Link DIR-600
- D-Link DIR-610
- D-Link DIR-615
- D-Link DIR-645
- D-Link DIR-815
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device takeover allowing attackers to install persistent backdoors, intercept all network traffic, pivot to internal networks, and use the router as part of botnets or for cryptocurrency mining.
Likely Case
Router compromise leading to DNS hijacking, credential theft from network traffic, and use as a proxy for malicious activities.
If Mitigated
Limited impact if routers are behind firewalls with strict inbound filtering, though internal exploitation remains possible.
🎯 Exploit Status
Exploitation requires a single HTTP POST request. Public proof-of-concept code is available. Evidence of active exploitation observed by Shadowserver Foundation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: N/A
Vendor Advisory: https://support.dlink.com/EndOfLifePolicy.aspx
Restart Required: No
Instructions:
No official patch available. D-Link has ended support for these models. Replace affected hardware with supported devices.
🔧 Temporary Workarounds
Disable remote administration
allTurn off remote management/administration features to prevent external exploitation
Network segmentation and filtering
allPlace routers in isolated network segments and implement strict firewall rules
🧯 If You Can't Patch
- Immediately replace affected routers with supported models
- Implement network monitoring and intrusion detection for suspicious HTTP POST requests to service.cgi
🔍 How to Verify
Check if Vulnerable:
Check router web interface for model and firmware version. If running affected firmware on listed models, assume vulnerable.Check Version:
Login to router web interface and check System Status or Firmware Information pageVerify Fix Applied:
Verify router has been replaced with supported hardware or test with controlled exploit attempt (not recommended in production).📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /service.cgi with EVENT=CHECKFW parameter containing shell metacharacters
- Unusual system command execution in router logs
Network Indicators:
- HTTP traffic to router on port 80/443 containing shell commands in POST data
- Outbound connections from router to suspicious IPs
SIEM Query:
source="router_logs" AND (url="/service.cgi" AND method="POST" AND (param="EVENT=CHECKFW" AND (content="|" OR content="$" OR content="&" OR content=";")))